BFN = HCG at 0?

This may be a stupid question, but after a mc, will a HPT give you a BFN only when your HCG is at 0, or at least where you can expect to get AF within the next 2 weeks? Or will some give you a BFN even at low HCG amounts that haven't cleared from your system yet? I'm guessing it might depend on the sensitivity of the test?

Comments (2)

Depends on the test. Some pregnancy tests have sensitivities of 25, 50 or even 100 HCG and will give a negative at levels below that. The most sensitive test is a FRER which has been shown to give a positive at levels as low as 6.

WSS^^^ It depends on the sensitivity of the test you are using. Anything under 5 is considered not pregnant via a blood draw but with urine tests you need to test with a sensitive test to "assume" you have a 0 level.